All missing stubs, refactor, build warnings, backwards compatibility.

[olivi-r]

Changes:

• Add stubs for all public methods
• Fix idl definition of IXSystemImpl
• Convert IXThreadingImpl and IXNetworkingImpl to idl definitions
• Fix build warnings, including 32-bit build
• Fix signatures for a couple of incorrect methods
• Interface inheritance for full backwards compatibility up to April 2026 release of GDK
• Remove unused IWineAsyncWorkImpl interface
• Sort Makefile.in sources to appease tools/make_makefiles
• Fix E_POINTER being thrown by XSystemGetConsoleId and XSystemGetXboxLiveSandboxId when missing their optional Used arguments (also found independantly by @ChristopherHX)
• Supersedes xgameprotocol: add stubs #31 and XLauncher Implementation #37
• Tests for the various interface ids (marked flaky to pass on old xgameruntime.dll)

Stubs for XUser are included here, but the actual implementation is in #33

Areas that could be improved:

• XPackageMount isn't stubbed due to inconsistent behaviour which sometimes calls the padding function on XError which is unclear if its the intended location or taking a shortcut to raising errors via private method, given that the method is deprecated.
• XGameStreaming, XGameUi and XPackage likely have additional interface iids used before the first public tag of GDK, games made with older non-public versions that haven't been updated could have limited compatibility

[olivi-r]

This should be complete now, but I can make further changes if you would like.

[RaphyTwin]

nice

[olivi-r]

Removed some left over static lib declarations